The sixth Kassam rocket fired into Israel by Palestinians on Friday hit a home in Sderot, lightly wounding a 17-year-old boy. Several others were treated for shock and the boy was evacuated to Barzilai Hospital in Ashkelon. Magen David Adom medics treated the other victims at the scene. The house sustained heavy damage in a barrage during which three other rockets landed in open areas in the western Negev town. Earlier Friday, two rockets were fired into the town causing no casualties or damage. In addition, Palestinians fired eight mortar shells into the Gaza periphery town of Netiv Hashayara on Friday afternoon. Most of the shells landed in open areas. No casualties or damage were reported. Overnight Thursday, IDF troops in the Gaza Strip killed two Hamas gunmen as Israel launched strikes against Palestinian terrorists that left 11 dead in 24 hours. The simmering conflict between Israel and Gaza's terror organizations has escalated less than a week before US President George W. Bush's visit to the region, overshadowing peace efforts and increasing the chances of a full-scale armed conflict in Gaza. On Thursday, Palestinian terrorists hit Israel with a Katyusha rocket, a weapon with a deadlier warhead and longer range than the smaller rockets the extremist groups regularly launch. It hit in the northern part of the town of Ashkelon, the longest reach yet for a Palestinian rocket. The IDF hit back Thursday with air strikes and ground operations that killed nine people, including three civilians. The operations continued Friday when infantrymen inside Gaza, near the Israeli border, clashed with Hamas gunmen and killed two of them, according to Hamas and Palestinian medical officials. Troops saw armed men approaching them and opened fire, the military said. Thursday's rocket strike caused no casualties. But Israel considers it an escalation, government spokesman David Baker said. "The Palestinians have attacked a major Israeli city ... and thus have upped the ante. Israel will not allow any cities to be attacked by Palestinian rocket fire," Baker said. The Ashkelon attack upped calls for a large-scale ground operation in Gaza to root out militants. Roni Mehatzri, Ashkelon's mayor, called for an Israeli invasion of Gaza to stop the attacks, now that his city of 120,000 is in range. "It's just madness, just madness," he told Channel 10. "Israel should have acted in Gaza a long time ago." But a senior Israeli official said Friday that Israel's current policy was working. "Hundreds of terrorists" have been killed by Israeli forces in Gaza over the past six months, Vice Premier Haim Ramon said, and Israel's policy of blockading Gaza has succeeded in undermining Hamas. "Hamas is under serious pressure, and is making efforts to convince other terror organizations in Gaza to hold their fire, hoping that we'll stop attacking it and its men. Hamas's hold on Gaza is getting weaker and weaker," Ramon told Israel Radio.